Interface sizing tool and method

ABSTRACT

A method and apparatus can be used in the selection of correctly sized respiratory interfaces. The method includes the use of light beams to project sizing markers onto a patient&#39;s face, which enables the size of the patient&#39;s facial features to be measured relative to a set of interface sizes. A sizing apparatus can include a light source and beam splitters that will refract and project the light source into a series of beams that can be aligned on a patient&#39;s face in order to measure the features of the patient.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference in their entireties andmade a part of the present disclosure.

BACKGROUND Field

The present disclosure generally relates to the selection ofappropriately sized respiratory interfaces. More particularly, thepresent disclosure relates to a method and apparatus for selecting anappropriately sized respiratory interface for use in providingrespiratory therapies, such as but not limited to positive airwaypressure (PAP) therapies (e.g., constant positive airway pressure (CPAP)therapy) and non-invasive ventilation (NIV).

Description of Related Art

There exists tools and methods that are currently employed to selectappropriately sized interfaces for patients. For example, a commonlyknown method and apparatus for selecting appropriately sized patientinterfaces includes the use of cardboard or plastic sizing guides tomeasure a patient's face. Sizing guides usually consist of a piece ofcardboard or plastic with markings and/or cut-outs that indicateinterface sizes. The sizing guide is then held against a patient's facein order to measure their facial features in relation to the availableinterface sizes and select the most appropriate interface size.

SUMMARY

It is common for sizing guides not to be used when selecting aninterface for a patient because of a number of problems related totraditional sizing guides. These problems can include hygiene orperceived hygiene, accessibility and ease of use. The sizing guides areoften included as an insert or as a part of the interface packaging.Packaging can be handled by many people before the product reaches thepatient, which may result in the sizing guide to be held against apatient's face being unhygienic or creating a concern in the patientthat the sizing guide is unhygienic. It is also possible that a singlesizing guide will be used to measure multiple patients. This situationmay also create a concern in the patient that the sizing guide has notbeen properly cleaned between uses and, thus, is unhygienic. It iscommon for packaging to be thrown away in order to minimize storagespace when a dealer or hospital has a large stock of interfaces. Thismeans that traditional sizing guides are often thrown away with thepackaging, which makes them inaccessible.

A traditional sizing guide may not be very easy to use because it can becumbersome or overly flexible. If the guide is too large, it may be anuisance to store and awkward to hold against a patient's face. If thesizing guide is too flexible, it may be difficult to hold against thepatients face and to achieve an accurate measurement.

Ineffective sizing tools often result in a trial and error approach toselecting interfaces. Typically the treatment provider will start off byproviding a patient with a medium size interface and change to adifferent size if necessary or desired. This results in a slow sizingprocess and, if the appropriate size is not identified and selected, canresult in ineffective or less-than-optimal treatment and/or discomfortfor the patient. In addition, this process can result in waste, such asinterfaces requiring sterilization or disposal after being used for ashort time on a patient for whom it is unsuitable.

The systems, methods and devices described herein have innovativeaspects, no single one of which is indispensable or solely responsiblefor their desirable attributes. Without limiting the scope of theclaims, some of the advantageous features will now be summarized.

Certain features, aspects and advantages of the present disclosureinclude a method and apparatus for measuring a patient's face and forselecting an appropriately sized respiratory interface. In someconfigurations, the method includes using a focused light source toproject markers onto a patient's face that correspond with or otherwiseindicate the sizes of a respiratory interface. The projected markers canthen be used to measure the patient's face to select the appropriateinterface size.

In some configurations, the apparatus includes a pen-like tool thatcontains at least one light source and provides a means for projectingbeams of light at predetermined spacings onto a patient's face. In someconfigurations, one or more beam splitters are used to project a beam oflight from the light source onto the patient's face.

By providing a tool in a pen-like form and by using light as ameasurement tool, certain of the problems experienced by traditionalsizing guides are addressed. The pen-like structure makes it convenientfor the person fitting a patient with a mask to carry the tool with themin his or her pocket. Thus, the tool is more likely to be accessible.Having a specific sizing tool that is reusable reduces or eliminates thestorage space required and makes it quicker and easier for medicalpractitioners, dealers or other service providers to size a patient. Inat least some configurations, the method is non-contact in that thepatient will not need to be touched by the sizing tool, the user of thesizing tool, or both in order to be measured. As a result, a singlemeasurement tool can be used for multiple people without hygiene issues.Benefits of selecting the correct interface size for a patient the firsttime include reduced waste and improved comfort, convenience andtreatment for the patient.

In some configurations, a method of measuring a patient's face in orderto select an appropriately sized respiratory interface involves a lightsource used to project sizing markers onto a patient's face.

In some configurations, a hand-held apparatus for mask sizing comprisesa light source and means of refracting and projecting markers onto apatient's face, wherein the hand-held apparatus is spaced away from thepatient's face in use. In some configurations the hand held apparatuscomprises one or more light manipulation arrangements that areconfigured to manipulate light from the light source and project one ormore markers onto a patient's face when the hand-held apparatus isspaced away from the patient's face. The one or more markers correspondsto a size of the interface.

In some configurations, an interface sizing tool comprises a body and alight source supported relative to the body. The light source isconfigured to project a beam of light. One or more light manipulationarrangements manipulate the beam of light to project one or more markersonto the face of a patient. A location of the one or more markerscorresponds to an interface size. The light manipulation arrangementscan affect one or more properties of the light beam.

In some configurations, each of the one or more markers is a beam oflight.

In some configurations, multiple light manipulation arrangements areprovided.

In some configurations, the beam of light from the light source passesthrough the multiple light manipulation arrangements, each lightmanipulation arrangement configured to partially manipulate the beam oflight from the light source to generate the one or more markers.

In some configurations, the light manipulation arrangement is a beamsplitter.

In some configurations, each marker is generated by splitting the beamof light from the light source into the one or more markers.

In some configurations, the multiple beam splitters are spaced apartfrom one another on the body.

In some configurations, the beam splitters are shaped and spaced suchthat the markers are spaced a predetermined distance from one another.

In some configurations, the spacing of two or more of the multiplemarkers corresponds to the size of the interface.

In some configurations, at least one lens is positioned in front of oneor more of the beam splitters and configured to focus the marker lightbeam.

In some configurations, a reference marker is generated by a referencebeam splitter.

In some configurations, each of the beam splitters refract only aportion of the incident beam of light from the light source such thatall of the markers are visible on the face of the patient.

In some configurations, at least one of the beam splitters is movablealong a length of the body.

In some configurations, the at least one movable beam splitter ismovable to two or more positions corresponding to two or more interfacesizes.

In some configurations, the body comprises a track and at least oneplatform movable within the track, wherein the each of the at least onemovable beam splitters is carried by one of the movable platforms.

In some configurations, a mechanism for moving the at least one movablebeam comprises a push button, a twist knob or a sliding switch.

In some configurations, the body comprises a clip that permits the toolto be attached to an object by the clip.

In some configurations, the tool comprises a laser pointer or writingtip.

In some configurations, a method of sizing a patient for an interfacecomprises projecting one or more markers generated by a light sourceonto the face of a patient. The size of an interface to be used on thepatient is determined based on the location of the one or more markers.

In some configurations, the projected markers include a reference markerand at least one sizing marker.

In some configurations, the reference marker is located relative to areference point or landmark on the face of the patient and the size ofthe interface is determined based on a location of the at least onesizing marker relative to another reference point or landmark on theface of the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers can be reused to indicategeneral correspondence between reference elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

FIG. 1 is a profile view of a sizing tool being used on a patient.

FIG. 2 is a schematic view of a sizing tool having a structure oroutward size and/or shape similar to a typical writing pen.

FIG. 3A is a diagram that demonstrates the effect of non-parallel lightbeams.

FIG. 3B is a diagram of an embodiment having two light beams for thereference marker and each sizing marker.

FIG. 4 is a block diagram of an exemplary process for determining anappropriate or desirable interface size for a patient.

DETAILED DESCRIPTION

Patient interfaces are used to provide respiratory therapies astreatment for a variety of conditions. Such therapies includenon-invasive ventilation (NIV) and positive airway pressure (PAP)therapies, such as continuous positive airway pressure (CPAP), forexample. For some respiratory therapies, it is desirable for treatmentefficacy and patient comfort that a good fit and seal is achievedbetween the interface and the patient. As such, it is advantageous tofit a patient with an interface that is a desirable or suitable size forthe patient. Certain features, aspects and advantages of the embodimentsdescribed herein provide a method and/or apparatus to achieve orfacilitate an interface size selection for patients.

In some configurations, the method involves the use of a light source ora plurality of light sources to project sizing one or more markers orindicators onto a patient's face. The markers or indicators are alignedwith and used to measure particular facial features or landmarks, thusallowing the selection of an interface size that fits the patient in adesired manner. In some configurations, the method is facilitated by asizing tool configured to create sizing markers or indicators thatcorrespond to one or more available sizes of an interface or otherwiseindicate or allow the determination of an appropriate or desirableinterface size (which could involve selection between available sizes ofa particular interface or facilitate the determination of a brand ormodel of interface that provides an appropriate or desirable fit, forexample).

In some configurations, the sizing tool is specific to a particular typeof interface (e.g., nasal mask or full face mask), brand of interfaces,line or family of interfaces or a single interface. For example, asizing tool that is particular to a single interface can project sizingmarkers or indicators onto a patient's face that correspond to theavailable seal sizes of the interface. The user can determine anappropriate or desirable size of interface or seal based on the markeror indicator located at or most appropriately located relative toparticular facial features of the patient. For example, the markerlocated closest to the relevant facial feature may not indicate theappropriate or desirable size of interface if the marker is on the wrongsize of the feature. That is, is may be desirable for the interface sealto contact the patient's face above (or below) the facial feature. Thus,the closest marker located above (or below) the facial feature mayindicate the appropriate or desirable size of interface even thoughanother marker is closer to the feature in absolute terms.

In other configurations, the sizing tool is configured or suitable foruse with a variety of interface types, brands or lines. For example, thesizing tool can be configured to provide or allow determination of ageneral measurement or characteristic of the patient's face, such as adistance between two locations (e.g., features or landmarks). Themeasurement taken by the sizing tool can then be used to select anappropriate or desirable size of interface. For example, the measurementcan be compared to data on interface size that relates to themeasurement and the comparison of the measurement to the data canfacilitate the selection of an appropriate or desirable interface. Forexample, if the measurement relates to a vertical distance between thesellion and sublabial locations of the patient, that measurement can becompared to the height dimensions of available interfaces or seal sizesto facilitate a selection of an appropriate or desirable interface.Other suitable facial locations, features or landmarks can also be used.

In some configurations, the sizing tool is adjustable and can beadjusted between two or more modes, each of which correspond to adifferent size, type, family, brand or other classification oridentifier of an interface. For example, in some arrangements, thesizing tool has one mode corresponding to one interface type (e.g., fullface mask) and another mode corresponding to another interface type(e.g., nasal mask). More than two modes may be provided. For example,there may be three, four, five or any other number of modes. In someconfigurations the sizing tool comprises a body, a light sourcesupported relative to the body, the light source configured to project abeam of light, one or more light manipulation or control arrangementsthat manipulate or control the beam of light to project one or moremarkers onto the face of a patient and wherein a location of the one ormore markers corresponds to an interface size. The one or more markersis a portion of the beam of light projected by the light source. Inother configurations the sizing tool comprises a plurality of lightsources spaced apart from one another along the body, the one or morelight sources configured to project a marker on to a user's face, eachmarker corresponding to an interface size. The markers can be individuallight beams from separate light sources or can be portions of a lightbeam from a single light source. The light manipulation or controlarrangements can be beam splitters, prisms, lenses or other devices thatcan manipulate and/or control light. In some alternative configurationsthe light manipulation or control arrangements may comprise a lightsource. In some other configurations the light manipulation or controlarrangements may comprise a light source and an associated device thatcan manipulate, split, bend or otherwise control light. In furtheralternative configurations the light manipulation or control arrangementcan be an optical device that allows light to pass through and affect atleast a property of the light, for example speed or direction etc. Thesizing tool may comprise an actuator, such as a switch or an on/offbutton, to activate and deactivate the light source(s).

As illustrated in FIG. 1 , a sizing tool 10 can be positioned near theface of a patient 12 such that one or more beams of light are projectedonto the face of the patient 12. In the illustrated configuration,multiple light beams are projected onto the face of the patient 12. Thelight beams are markers or indicators that can be utilized by the userof the sizing tool 10 to facilitate selection of an appropriate ordesirable size of an interface. In the illustrated arrangement, thesizing tool 10 is similar in size and/or shape to a typical writing pen.Thus, the sizing tool 10 is a handheld device sized, shaped and of aweight that allows the tool 10 to be conveniently held in the hand of auser. The sizing tool 10 can be an elongate member having a length thatis significantly greater than the diameter, width or depth. In someconfigurations, the sizing tool 10 can be about 10-20 cm in length.However, the sizing tool 10 can be provided in other shapes and sizes,including non-portable configurations. For example, the sizing tool 10may comprise, or be mounted on, a fixed or self-supporting device suchas a stand, or bracket or base or the like. The sizing tool 10 may beremovably mounted on such a device.

In the illustrated arrangement, a first light beam 14 is a referencelight beam, which can be aligned with a particular location, feature orlandmark on the face of the patient 12 by the user of the sizing tool10. One or more additional light beams are projected onto the face ofthe patient 12 at a location or locations spaced from the first lightbeam 14. These one or more additional light beams can be utilized toindicate an appropriate or desirable size of an interface.

In the illustrated arrangement, multiple light beams are provided inaddition to the first light beam 14. For example, three sizing lightbeams 16, 18, 20 are provided in addition to the first light beam 14.These light beams 16, 18, 20 are referred to as second, third and fourthlight beams, respectively. The second light beam 16, third light beam 18and fourth light beam 20 can correspond to three different availablesizes of an interface, such as small, medium and large, for example.Accordingly, the second light beam 16 can be referred to as the smallindicator or marker, or small light beam. Similarly, the third lightbeam 18 can be referred to as the medium indicator or marker, or mediumlight beam and the fourth light beam 20 can be referred to as the largeindicator or marker, or large light beam. In other configurations, alesser number (e.g., two) or a greater number (e.g., four or five) oflight beams or size indicators or markers can be provided.

In the illustrated positioning of the sizing tool 10, the first lightbeam 14 is located at an upper location or relatively above or higherthan the other light beams 16, 18, 20. In particular, the first lightbeam 14 is located on the nose of the patient 12, such as at the sellion22 or the deepest point between the nose and the forehead. However, thefirst light beam 14 can be located at other locations, such as otherfacial landmarks or reference points. In some configurations, thelocation of the first light beam 14 corresponds to a location at whichthe interface seal contacts the patient 12. In other configurations, thelocation of the first light beam 14 can be spaced from a location atwhich the interface seal contacts the patient 12, such as at a landmarkthat is more easily identified and can be related to a location at whichthe interface seal contacts the patient 12. Such a landmark can be thesellion 22, for example, in situations in which the interface sealcontacts the patient 12 at a location other than the sellion 22. It willbe appreciated that an interface seal may not contact all patients atthe same location due to the wide variation in facial geometry betweenpatients. Thus, the first light beam 14 can be located at or near alandmark or feature on the face of the patient 12 that is sufficientlyclose to the location at which the interface seal contacts the patient12 such that appropriate sizing of the interface can be accomplished.

As illustrated in FIG. 1 , the small, medium and large light beams 16,18, 20 are projected at different locations on the face of the patient12 when the first or reference light beam 14 is located at the desiredlocation. The small, medium and large light beams 16, 18, 20 are locatedat different vertical distances from the reference light beam 14. Thelocations of the small, medium and large light beams 16, 18, 20 mayapproximate or correspond with locations at which the seals of thesmall, medium and large interfaces contact the face of the patient 12.The user of the sizing tool 10 can determine which of the small, mediumand large light beams 16, 18, 20 is best located relative to a featureor features of the face of the patient 12 to provide a desired fit ofthe interface. Based on that determination, an appropriate or desiredinterface size can be selected. For example, in the illustratedarrangement, the user may determine that the small light beam 16 is tooclose to the mouth of the patient 12 and that the large light beam 20 istoo close the chin of the patient 20 such that the small and largeinterfaces will be undesirably small and undesirably large,respectively. The user may determine that the medium light beam 18 is atthe most appropriate location on the face of the patient 12 anddetermine that the medium interface will provide an appropriate ordesirable fit.

Although the reference light beam 14 is illustrated as projecting at alocation higher than the locations of the small, medium and large lightbeams 16, 18, 20, on an upper portion of the face of the patient 12 oron the nose of the patient 12, in other configurations, this orientationcould be reversed. For example, the reference light beam 14 could belocated lower than the sizing light beams, such as the small, medium andlarge light beams 16, 18, 20. In some configurations, the referencelight beam 14 can be located on a lower portion of the face of thepatient 12, such as between the lower lip and chin or at a sublabialpoint and the sizing light beams (e.g., locations of the small, mediumand large light beams 16, 18, 20) can be located on or near the nose ofthe patient 12 and the appropriate sizing light beam can be selectedbased on a reference point or landmark on an upper portion of the faceof the patient 12.

In one embodiment, certain features, aspects and advantages involve amethod and an apparatus involving a sizing or measuring tool 10 in theform of a pen-like structure that is provided with at least one lightsource and is configured to split, focus and project the light atpredetermined spaced locations that correlate to interface sizes so thatthe projections can be used to measure a patient's face. In use, themeasuring tool is held at a distance in front of a patient's face andlight markers will be projected onto the face of the patient and used asa measurement scale.

FIG. 2 illustrates a schematic view of one embodiment of the sizing tool10. The illustrated sizing tool 10 is pen-like in structure in that itis of a similar shape and size to a common writing pen. The pen-likesize and shape makes the tool 10 easy to store, carry and handle. Thetool 10 includes a light source 30, an on/off button or other control32, several beam splitters 34 and a lens 36 that refracts and projectsthe beam emitted from the light source 30.

In some configurations, the light source 30 is a class one laser or LEDunit that provides a single beam of light 30 a that is aimedlongitudinally along the length of the tool 10. A class one laserprovides the advantage of being safe when directed towards a patient'seyes. If an LED light source is used, a focusing system can be providedto create the desired single defined beam of light 30 a.

Along the length of the tool 10, there can be a number of beam splitters34 that cause the beam of light 30 a from the light source 30 to berefracted and thus projected from the tool 10 at a predetermined angle.In some configurations, the beam of light is projected perpendicularlyto the longitudinal axis of the tool 10 and/or perpendicularly from thedirection that the beam of light 30 a is projected from the light source30. In some configurations, there are four beam splitters 34 or one beamsplitter 34 for each desired projecting beam or marker. The first beamsplitter 34 a can correspond to a reference point used to measureinterface size. The beams 16, 18, 20 (FIG. 1 ) emanating from the threeother beam splitters 34 b, 34 c, 34 d, respectively, can correlate tothe different interface sizes (e.g., small, medium and large). The threesizing splitters 34 b, 34 c, 34 d are located at points along the tool10 that correlate to a predetermined geometric feature of the faceand/or interfaces. For example, in the case of a full-face interfacethat encircles the patient's nose and mouth, the reference point can bethe bridge of the nose. This means that, when using the tool 10, thefirst projected marker 14 (FIG. 1 ) is aligned with the bridge of thepatient's nose. This point generally or substantially corresponds to theuppermost contact point that the interface would have with the patient'snose. The sizing splitters 34 b, 34 c, 34 d can be spaced from thereference splitter 34 a such that they match the distance between thebridge of the nose or uppermost contact point of the interface and thelowest sealing point on or under the patient's chin, for each of theinterface sizes.

In another embodiment, a manual mechanism can be used to position anindividual sizing beam splitter at set positions along the tool thatcorrespond to the different interface sizes. In some suchconfigurations, only two beams of light will be projected onto thepatient: a reference marker and a sizing marker. However, multiplesizing markers could be used in such an arrangement. The sizing markercan be moved between the different sizing positions, which can beindicated by the tool, such as by printed indicators, detents or otherindicia. The manual adjustment mechanism can be of any suitablearrangement, such as a track 37 and a platform 38 that moves within thetrack 37 and carries the beam splitter 36, as illustrated in connectionwith one of the splitters 36 of FIG. 2 . The platform 38 can becontrolled by any suitable actuation arrangement, such as a twist knob,push-button, sliding switch 39 or other mechanism that adjusts theposition of the sizing beam splitter relative to the tool and/orreference marker. In some configurations, an individual beam splitter isprovided for each interface size and each of the individual beamsplitters can be selectively moved in or out of the path of the lightsource by the manual mechanism. In such a configuration, there can betwo projected markers at any time. In some configurations, a single toolcan be used to select sizes for multiple interface families. Having asingle tool that can be used to size a patient for a variety ofdifferent interface types while not contacting the patient's face,including but not limited to full-face, nasal, pillows and cannula PAP(e.g., CPAP) and NIV interfaces, will make the tool more useful andconvenient. A twist knob or other such mechanism can be used to select aparticular interface family by moving the beam splitters to positionsthat correspond to the sizes of the selected interface family.

In some configurations, the light beam is only partially refracted bythe beam splitters 34 allowing some of the light to pass through each ofthe splitters 34 thus reaching the last splitter (e.g., 34 d or thesplitter 34 further from light source 30) without being completelydiminished. Preferably, the light beam reaches the last splitter 34 dwith enough strength such that the last light beam 20 (FIG. 1 ) producesa visible marker on the face of the patient 12. The beam splitters 34can be of a triangular geometry or any other geometry that is capable ofrefracting the light beam by a predetermined or other desirable angle.

In front of each beam splitter 34 can be a lens 36 that manipulates therefracted light beam. For example, the lens 36 can be configured tofurther refract the beam of light so that a line of light is projectedonto the patient's face rather than a single point of light. In order toachieve this refraction the lenses 36 can have a semi-circular orhalf-round cross-sectional profile. The lenses 36 can be made fromacrylic glass (e.g., poly methyl methacrylate) or other materials withsimilar optical properties. In some embodiments, a single lens extendsthe entire length of the sizing tool and interacts with some or all ofthe refracted light beams 14, 16, 18, 20.

In some embodiments, the tool 10 incorporates a pen or laser pointerdevice 40 at the end opposing the light source 30. This arrangementprovides the tool 10 with a secondary purpose and makes it more usefuland hence more likely to be used. Other common characteristics of pens,such as a pocket clip 42 or lanyard attachment can be included toincrease ease of use and convenience.

Alignment of the beam splitters 36 can have an impact on the usabilityand accuracy of the tool 10. The beam splitters 36 can be angled todirect the refracted light beam at a predetermined angle relative to thedirection of light beam from the light source 30. Preferably, each ofthe beam splitters 36 is configured to refract the light such that eachof the split beams 14, 16, 18, 20 is parallel to the others. Thisarrangement reduces the likelihood of distortion of the distance betweenprojected markers as the tool 10 is held at different distances from thepatient 12 being measured, as shown in FIG. 3A. FIG. 3A illustrates anexaggerated view of the distortion of the distances Y1 and Y2 betweenprojected reference and sizing markers 14 and 20, respectively, thatresult from non-parallel beams when the tool 10 is held at differentdistances X1 and X2 from the patient 12. Although not specificallydesignated, FIG. 3A illustrates distortion of sizing markers 16 and 18as a result of being non-parallel with reference marker 14.

In some configurations, the tool can include two or more light sources.In configurations using two light sources, as illustrated in FIG. 3B,the light sources can be refracted to create two beams for each of thesizing markers (16 a, 16 b, 18 a, 18 b, 20 a, 20 a, 20 b) and thereference marker (14 a, 14 b). When the tool is held at thepredetermined distance and angle to the patient's face, the refractedbeams will intersect with each other to create a single focused markerpoint (P_(R), P_(S1), P_(S2), P_(S3)) on the patient's face (i.e., eachsizing marker and the reference marker will be generated by two lightbeams). Such an arrangement can reduce or minimize any measurementdistortion generated as a result of the tool 10 being held at anincorrect angle or distance from the patient's face by allowing the userto determine when the tool 10 is held at the correct distance. That is,the user can adjust the distance of the tool 10 relative to thepatient's face until one or more of the reference marker and sizingmarker(s) project a point on the patient's face (or line in the case ofa line marker, as described above).

In at least one configuration, the light beam from the light source 30can be further split or manipulated and used to project symbols onto theface of the patient 12, which symbols may indicate which interface sizeeach of the projected markers correlates to (e.g., an ‘S’, ‘M’, or ‘L’can be used to indicate ‘small’, ‘medium’ and ‘large’ respectively). Thesymbols can be configured to come into focus when the tool is held anappropriate distance from the patient's face, similar to the arrangementdescribed above, to provide an indication to the user of when the tool10 is at a proper distance. In some configurations, individual lightsources can be used to project the symbols or one or more (e.g., each)of the reference or marker light beams.

FIG. 4 illustrates a block diagram of a method or process 50 fordetermining a size of an interface for a particular patient. The process50 can utilize a sizing tool, such as any of the sizing tools 10disclosed herein, or can utilize other types of sizing tools or otherdevices for projecting beams of light onto the face of a patient. Asdescribed herein, determining an appropriate or desirable size ofinterface can include selecting a particular interface or seal sizebetween available sizes of a particular interface. The determining of anappropriate or desirable size can broader in scope, such as determiningan appropriate brand or model of interface for the particular patient.

At block 52, a reference marker is projected onto the face of thepatient. The reference marker preferably is a beam of light, which canbe a point, a line or another suitable shape as projected on thepatient. The reference marker preferably is projected by a user of asizing tool by powering on the tool, if necessary, and positioning thetool at a suitable location and orientation relative to the patient'sface such that the reference marker is projected onto the patient'sface.

A block 54, the reference marker is located relative to a referencepoint or other location on the patient's face. The reference marker canbe located at the reference point or location or can be located at adistance from a reference point (e.g., 5 mm below the sellion). Thereference point or location can be any suitable feature or landmark onthe patient's face and, in at least some configurations, is located at,near, relative to or otherwise corresponds to a location on thepatient's face that is contacted by the interface seal. The referencepoint can be located at or near an uppermost point of contact betweenthe interface seal and the patient or a lowermost point of contactbetween the interface seal and the patient. In other arrangements,sizing may be determined by a horizontal measurement, in which case thereference marker can be located at a suitable lateral location on thepatient's face (e.g., outward of one side of the mouth).

At block 56, a least one sizing marker is projected onto the patient'sface. In some configurations, multiple sizing markers are projected ontothe patient's face. The multiple sizing markers can correspond toavailable sizes of an interface, for example.

At block 58, a size of interface is determined based on a location ofthe at least one sizing marker on the patient's face. Preferably, theuser of the sizing tool or other projecting device makes thedetermination based on the location of the sizing marker(s). Thedetermination can involve the location of the sizing marker(s) relativeto a landmark or other feature of the patient's face. In someconfigurations, the sizing landmark or feature is located at, near,relative to or otherwise corresponds to a location on the patient's facethat is contacted by the interface seal. The sizing landmark or featurecan be located at or near a lowermost point of contact between theinterface seal and the patient or an uppermost point of contact betweenthe interface seal and the patient. In other arrangements, sizing may bedetermined by a horizontal measurement, in which case the referencemarker can be located at a suitable lateral location on the patient'sface (e.g., outward of one side of the mouth). In configurations withmultiple sizing markers, the determination can involve selection of thesizing marker most appropriately located relative to the sizing landmarkor feature, which can be the closest marker in absolute terms or can bethe closest marker that is appropriately positioned relative to thesizing landmark or feature. For example, the appropriate sizing markercan be the marker closest to the sizing landmark or feature that islocated on a particular side (e.g., above, below, inward or outward) ofthe sizing landmark or feature.

The activities associated with blocks 52, 54, 56 and 58 are notnecessarily performed in the order illustrated and described. Forexample, in some configurations, the projection of the reference markerand sizing marker(s) can occur simultaneously. In addition, otheractivities can be performed as well. For example, the sizing tool can bemoved to focus a reference marker or other location indicator on thepatient's face to verify proper location of the sizing tool, asdescribed above. In some configurations, the process includes moving thelocation of a sizing marker relative to the reference marker. In suchconfigurations, the determination of an appropriate or desirableinterface size can involve determining the position of the sizing markerrelative to the reference marker once the sizing marker is located at anappropriate or desirable distance from the reference marker. Forexample, the user can read the location of the sizing marker based onlocation indicia provided on the sizing tool (e.g., a size scale ordetent location).

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to”.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the invention and withoutdiminishing its attendant advantages. For instance, various componentsmay be repositioned as desired. It is therefore intended that suchchanges and modifications be included within the scope of the invention.Moreover, not all of the features, aspects and advantages arenecessarily required to practice the present invention. Accordingly, thescope of the present invention is intended to be defined only by theclaims that follow.

1. An interface sizing tool, comprising: a body; a light sourcesupported relative to the body, the light source configured to project abeam of light; one or more light manipulation arrangements thatmanipulate the beam of light to project one or more markers onto theface of a patient; wherein a location of the one or more markerscorresponds to an interface size.
 2. The interface sizing tool of claim1, wherein each of the one or more markers is a beam of light.
 3. Theinterface sizing tool of claim 1, wherein multiple light manipulationarrangements are provided.
 4. The interface sizing tool of claim 1,wherein the beam of light from the light source passes through themultiple light manipulation arrangements, each light manipulationarrangement configured to partially manipulate the beam of light fromthe light source to generate the one or more markers.
 5. The interfacesizing tool of claim 1, wherein the light manipulation arrangement is abeam splitter.
 6. The interface sizing tool of claim 5, wherein eachmarker is generated by splitting the beam of light from the light sourceinto the one or more markers.
 7. The interface sizing tool of claim 1,wherein the multiple beam splitters are spaced apart from one another onthe body.
 8. The interface sizing tool of claim 7, wherein the beamsplitters are shaped and spaced such that the markers are spaced apredetermined distance from one another.
 9. The interface sizing tool ofclaim 1, wherein the spacing of two or more of the multiple markerscorresponds to the size of the interface.
 10. The interface sizing toolof claim 1, further comprising at least one lens positioned in front ofone or more of the beam splitters and configured to focus the markerlight beam.
 11. The interface sizing tool of claim 1, wherein areference marker is generated by a reference beam splitter.
 12. Theinterface sizing tool of claim 1, wherein each of the beam splittersrefract only a portion of the incident beam of light from the lightsource such that all of the markers are visible on the face of thepatient.
 13. The interface sizing tool of claim 12, wherein at least oneof the beam splitters is movable along a length of the body.
 14. Theinterface sizing tool of claim 13, wherein the at least one movable beamsplitter is movable to two or more positions corresponding to two ormore interface sizes.
 15. The interface sizing tool of claim 1, whereinthe body comprises a track and at least one platform movable within thetrack, wherein the each of the at least one movable beam splitters iscarried by one of the movable platforms.
 16. The interface sizing toolof claim 1, wherein a mechanism for moving the at least one movable beamcomprises a push button, a twist knob or a sliding switch.
 17. Theinterface sizing tool of claim 1, wherein the body comprises a clip thatpermits the tool to be attached to an object by the clip.
 18. Theinterface sizing tool of claim 1, wherein the tool comprises a laserpointer or writing tip.
 19. A method of sizing a patient for aninterface, comprising: projecting one or more markers generated by alight source onto the face of a patient; determining the size of aninterface to be used on the patient based on the location of the one ormore markers.
 20. The method of claim 19, wherein the projection one ormore markers comprises projecting a reference marker and at least onesizing marker.
 21. (canceled)